IMMUNITY 219 



scarcely worthy of the name, they differ so little from mere 

 critical statements of experimental results. Even at the risk 

 of being regarded as incapable of generalizing, I prefer to stick 

 to the facts without moulding them into a system." 



In immunity phenomena, we observe certain activities ; but 

 why materialize them and picture each by an atomic group ? 

 In the side-chain theory we are told that the antibody is 

 nothing but a cell-receptor affected by the antigen. This 

 identity is not proved. Why should not the cell with its 

 power of adaptation and reaction produce some new and 

 original substance ? 



When the " substance " which we call agglutinin clumps 

 cells or bacteria, does it really bring into action an atomic 

 group, or side-chain, which attaches itself and another group 

 which agglutinates ? The explanation is artificial. In reality 

 it is not the agglutinin which agglutinates ; it is a salt. The 

 antigen (bacteria) and the antibody (agglutinin) form a com- 

 bination which produces floccules, or, as it is expressed 

 nowadays, is " flocculable " by electrolytes. It is this couple 

 or " complex " which agglutinates. 1 



An analogous coupling must be regarded as taking place in 

 all the reactions of antigens and antibodies, and Ehrlich's 

 theory is wrong in attributing everything to the antibodies 

 and nothing to the antigen. There are no " amboceptors " 

 in reality, there only exist " uniceptors " capable of being 

 absorbed. 



It was therefore not with the purpose of disputing details 

 that Bordet accumulated his experiments on the mode of 

 fixation of the complement on the immune body ; in this 

 field he has discovered the principal facts which render the 

 side-chain theory impossible as a dogma, if not altogether 

 impossible as a conception of certain phenomena. The 

 important fact is that there is never absorption of complement 

 by an immune body without the presence of an antigen, so 



1 The salt acts on bacteria saturated with agglutinin but it acts also on 

 bacteria which have absorbed various chemical substances, iron, uranium, 

 or aluminium. 



